Propagation success of grapevines (Vitis vinifera L.) infected with Xylella fastidiosa

Pierce's disease of grapes, caused by the xylem-limited bacterium Xylella fastidiosa Wells, is typically fatal to varieties of Vitis vinifera L. The objective of this study was to investigate rooting success of asexually propagated cuttings taken from X. fastidiosa infected grapevines and determine if rooted cuttings could survive and produce viable plants for vineyard establishment. Cuttings were taken January 2008 from dormant V. vinifera cv. Merlot and cv. Cabernet Sauvignon grapevines located in the Hill Country and Gulf Coast regions of Central Texas. Prior to our research, symptoms of Pierce's disease were recorded on each grapevine in each vineyard using a Symptomatic Reliability Index.

At the conclusion of six weeks, cuttings were uprooted and evaluated. Rooting percentage, number of roots, root length, root rating, number of shoots, and shoot length, were recorded for each cutting.

Rooting data indicates symptomatic and asymptomatic X. fastidiosa infected grapevines have the ability to be propagated asexually through cuttings. To confirm the presence of X. fastidiosa, rooted cuttings were tested with Enzyme-Linked ImmunoSorbent Assay and Real-time Polymerase Chain Reaction. Results revealed several asymptomatic and symptomatic cuttings positive for X. fastidiosa. This experiment demonstrated grapevine cuttings infected with X. fastidiosa can be propagated to produce healthy looking nursery plants that could be sold as clean nursery stock.